Showing posts with label octagon. Show all posts
Showing posts with label octagon. Show all posts

5 Nov 2021

Ely Cathedral Octagon - NOT amateur radio

This image (or one very similar) has been on the blog before, but I make no apologies. 

The very heavy wooden octagon replaces the original tower that collapsed centuries ago. The octagon dates from 1342. 

Imagine designing and constructing this back then!

18 Jun 2013

Low cost, high performance 10GHz receiver

Recently Ian G3KKD has been telling me about some remarkable results on 10GHz using an Octagon satellite LNB that is available for around £12-15 via eBay. This has a crystal controlled PLL and has good frequency accuracy, stability and phase noise. I believe the LNB outputs a signal around 600MHz which is then down converted to a suitable IF.

Using this set-up Ian can copy the 10GHz beacon GB3CAM at around 30km with just the LNB handheld in his front or back garden which is badly screened by tall trees! Using a small Sky dish, the signal is S9+60dB from a point just along the road.

Of course, with a small surplus satellite dish, a low cost TV USB dongle used as an SSB/CW RX at the LNB output frequency, this would make an excellent SDR for 10GHz with VERY low noise figure. The LNB quotes the NF as 0.1dB, which is remarkable.

With a small 10GHz FM or CW TX into a separate dish, a complete low cost 10GHz station is possible, probably for less than £50. I am sorely tempted to try this.

I have just seen Andy G4JNT's note about this http://www.g4jnt.com/PLL_LNB_Tests.pdf .